Cryobostryxite
A valid IMA mineral species
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About Cryobostryxite
Formula:
KZnCl3 · 2H2O
Colour:
Colorless
Lustre:
Vitreous
Hardness:
2
Specific Gravity:
2.30
Crystal System:
Monoclinic
Name:
The mineral name is based on two Greek words, κρύος, cold or ice, and βóστρυξ, curl, reflecting the typical appearance: visually, anthodites of the mineral are very similar to ice curls.
Chemically related to flinteite and mellizinkalite (both anhydrous).
In the structure there are isolated Zn-centered ZnCl3(H2O) tetrahedra connected with KCl7(H2O) polyhedra to constitute a framework. Water in the above polyhedra contains O(1) atoms only. H2O(2) molecules reside within holes of the above pseudo-framework.
In the structure there are isolated Zn-centered ZnCl3(H2O) tetrahedra connected with KCl7(H2O) polyhedra to constitute a framework. Water in the above polyhedra contains O(1) atoms only. H2O(2) molecules reside within holes of the above pseudo-framework.
Unique Identifiers
Mindat ID:
46440
Long-form identifier:
mindat:1:1:46440:8
IMA Classification of Cryobostryxite
Classification of Cryobostryxite
3.BA.20
3 : HALIDES
B : Simple halides, with H2O
A : M:X = 1:1 and 2:3
3 : HALIDES
B : Simple halides, with H2O
A : M:X = 1:1 and 2:3
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Cbx | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Cryobostryxite
Vitreous
Transparency:
Transparent
Colour:
Colorless
Streak:
White
Hardness:
2 on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Parting:
None obeserved.
Fracture:
Irregular/Uneven
Density:
2.30(2) g/cm3 (Measured) 2.300 g/cm3 (Calculated)
Optical Data of Cryobostryxite
Type:
Biaxial (+)
RI values:
nα = 1.522(2) nβ = 1.530(2) nγ = 1.576(3)
2V:
Measured: 30° (15), Calculated: 46°
Max. Birefringence:
δ = 0.054
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Moderate
Dispersion:
None.
Optical Extinction:
Plane of optical axes is (010); Z ∧ c = 26°.
Pleochroism:
Non-pleochroic
Chemistry of Cryobostryxite
Mindat Formula:
KZnCl3 · 2H2O
Element Weights:
Common Impurities:
Tl
Crystallography of Cryobostryxite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/c
Cell Parameters:
a = 6.2795(3) Å, b = 10.1397(3) Å, c = 12.0829(7) Å
β = 107.732(5)°, γ = 107.732(5)°
β = 107.732(5)°, γ = 107.732(5)°
Ratio:
a:b:c = 0.619 : 1 : 1.192
Unit Cell V:
732.79 ų
Z:
4
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.62 Å | (30) |
| 5.986 Å | (43) |
| 5.766 Å | (35) |
| 3.907 Å | (33) |
| 3.466 Å | (20) |
| 3.062 Å | (100) |
| 2.996 Å | (24) |
| 2.853 Å | (27) |
Comments:
Northern fumarole field, First scoria cone, Tolbachik Volcanic field, Russia. Data from the type description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 45b : [Other oxidized fumarolic minerals] |
Type Occurrence of Cryobostryxite
General Appearance of Type Material:
Anthodites (up to 0.5 × 2 mm), their aggregates (up to 4 × 5 mm), granular crusts (up to 2 × 2 mm) and, rarely, coarse prismatic to acicular crystals (up to 0.2 × 1 mm).
Place of Conservation of Type Material:
Type material is deposited in the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia, registration number 4576/1.
Geological Setting of Type Material:
Secondary mineral formed in the upper, moderately hot (30–80 °C) zone of active fumaroles, probably as a product of the interactions between high-temperature volcanic sublimates and meteoric water. Formed on the surface of basalt scoria.
Associated Minerals at Type Locality:
Synonyms of Cryobostryxite
Other Language Names for Cryobostryxite
Dutch:Cryobostryxiet
German:Cryobostryxit
Common Associates
Related Minerals - Strunz-mindat Grouping
| 3.BA.05 | Hydrohalite | NaCl · 2H2O |
| 3.BA.10 | Carnallite | KMgCl3 · 6H2O |
| 3.BA.15 | Novograblenovite | (NH4)MgCl3 · 6H2O |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 0.0000% | 0 | α, β, γ |
| Thorium (Th) | 0.0000% | 0 | α, β, γ |
| Potassium (K) | 15.8377% | 4,910 | β, γ |
For comparison:
- Banana: ~15 Bq per fruit
- Granite: 1,000–3,000 Bq/kg
- EU exemption limit: 10,000 Bq/kg
Note: Risk is shown relative to daily recommended maximum exposure to non-background radiation of 1000 µSv/year. Note that natural background radiation averages around 2400 µSv/year so in reality these risks are probably extremely overstated! With infrequent handling and safe storage natural radioactive minerals do not usually pose much risk.
Interactive Simulator:
Note: The mass selector refers to the mass of radioactive mineral present, not the full specimen, also be aware that the matrix may also be radioactive, possibly more radioactive than this mineral!
Activity: –
| Distance | Dose rate | Risk |
|---|---|---|
| 1 cm | ||
| 10 cm | ||
| 1 m |
The external dose rate (D) from a radioactive mineral is estimated by summing the gamma radiation contributions from its Uranium, Thorium, and Potassium content, disregarding daughter-product which may have a significant effect in some cases (eg 'pitchblende'). This involves multiplying the activity (A, in Bq) of each element by its specific gamma ray constant (Γ), which accounts for its unique gamma emissions. The total unshielded dose at 1 cm is then scaled by the square of the distance (r, in cm) and multiplied by a shielding factor (μshield). This calculation provides a 'worst-case' or 'maximum risk' estimate because it assumes the sample is a point source and entirely neglects any self-shielding where radiation is absorbed within the mineral itself, meaning actual doses will typically be lower. The resulting dose rate (D) is expressed in microsieverts per hour (μSv/h).
D = ((AU × ΓU) + (ATh × ΓTh) + (AK × ΓK)) / r2 × μshield
Other Information
IR Spectrum:
O–H stretching (3200–3600 cm-1) and H–O–H bending (1607 cm-1), vibrations of H2O molecules as a whole (508 cm-1). A band at 3590 cm-1 and a doublet 3533 + 3520 cm-1 conform with weak hydrogen bonds formed by the atoms H3 and H4. Bands at 3372 and 3210 cm-1 conform with strong hydrogen bonds formed by the atoms H1 and H2. Weak bands in the range 600–1200 cm-1 correspond to overtones and combination modes. Absorptions corresponding to B–O, C–O, N–O and N–H bonds are absent.
Notes:
Readily dissolves in H2O at room temperature.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Cryobostryxite
mindat.org URL:
https://www.mindat.org/min-46440.html
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References for Cryobostryxite
Reference List:
Süsse, Peter; Brehler, Bruno (1964) Die Kristallstruktur des KZnCl3·2H2O. Beiträge zur Mineralogie und Petrographie, 10 (1). 132-140 doi:10.1007/bf01192542(synthetic)
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2014) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC), CNMNC Newsletter No. 22. Mineralogical Magazine, 78 (5) 1241-1248 doi:10.1180/minmag.2014.078.5.10
Pekov, Igor V., Zubkova, Natalia V., Britvin, Sergey N., Yapaskurt, Vasiliy O., Chukanov, Nikita V., Lykova, Inna S., Sidorov, Evgeny G., Pushcharovsky, Dmitry Yu. (2015) New zinc and potassium chlorides from fumaroles of the Tolbachik volcano, Kamchatka, Russia: mineral data and crystal chemistry. III. Cryobostryxite, KZnCl3·2H2O. European Journal of Mineralogy, 27 (6) 805-812 doi:10.1127/ejm/2015/0027-2482
Localities for Cryobostryxite
Showing 1 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Russia (TL) | |
| Williams et al. (2014) +2 other references |
Quick NavTopAbout CryobostryxiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatRadioactivityOther InformationInternet Links References Localities Locality List
Northern fumarole field, First scoria cone, Northern Breakthrough, Great Fissure eruption, Tolbachik Volcanic field, Milkovsky District, Kamchatka Krai, Russia